Vehicles such as electric vehicles (EV) and plug-in hybrid vehicles (PHV) include a rechargeable battery such as a lithium-ion battery. The rechargeable battery is used as a power storage device that stores electric power supplied to a drive source, which is an electric motor. The rechargeable battery includes an electrode assembly accommodated in a case. The electrode assembly is configured by, for example, stacking or winding strip-shaped positive electrodes and negative electrodes with separators located in between. Active material layers are formed on both sides of each of the positive electrodes and the negative electrodes.
Such a rechargeable battery includes a mechanism that interrupts or reduces current in a current-carrying path between the electrode assembly and an electrode terminal and a pressure release valve (for example, refer to Patent Document 1). The rechargeable battery of Patent Document 1 includes a mechanism that interrupts current (hereinafter, referred to as a current interruption mechanism). If the internal pressure of the case reaches a specified activation pressure due to generation of gas at the time of overcharging and overdischarging, the current interruption mechanism interrupts the current-carrying path and stops the overcharging and overdischarging state to prevent increase in the internal pressure caused by generation of gas. If the internal pressure of the case is increased and reaches the specified activation pressure, the pressure release valve is ruptured and releases the gas to the outside of the case to prevent increase in the internal pressure.
In the rechargeable battery that includes the above-mentioned mechanism that interrupts or reduces current and the pressure release valve, the activation pressure of the pressure release valve is set to a value higher than the activation pressure of the mechanism that interrupts or reduces current. Thus, if the increase in the internal pressure cannot be limited by interrupting or reducing the current, the pressure release valve is activated to limit the increase in the internal pressure of the case.